Wireless communication relies upon access to a portion of the electromagnetic spectrum suitable for use for carriage of signals for reception by passive antennas. This portion of the spectrum is commonly known as the radio spectrum.
The radio spectrum provides a finite resource for use by a variety of operators. The use of the radio spectrum is very often Government regulated, and is considered a public asset of a strategic nature. This, and the physical bound of the radio spectrum, imposes a limit on the design of cellular radio systems.
Rather than allocating parts of the radio spectrum for exclusive use by particular operators, various forms of sharing of bands have been established. A variety of communications protocols allow operators to organise the manner in which they will share a particular band of frequency for intermittent, occasional or constant use.
In practice, all sharing methods involve some form of interference, which is proportional to the power of transmitted signals. For voice services, transmitter power control has been shown to improve performance by balancing signals and with respect to interference.
As the demand for transmission of data by wireless means increases, the allocation of resource to satisfy diverse quality of service (QoS) requirements is of interest. Since the characteristics of data services differ from those of voice services, a different approach to transmission needs to be investigated.